Reciprocal interactions between the sorghum root microbiome and the parasitic weedStriga hermonthica

Abstract

SummaryThe soil microbiome plays a crucial role in protecting plants against various pests and pathogens. However, its impact on interactions between plants and parasitic weeds, such asStriga hermonthica, is poorly understood. In this study, sorghum plants susceptible toStrigawere grown in 22 different field soils infested with parasite seeds. Significant variations inStrigainfections were observed among the soils. When the mostStriga-suppressive soil was gamma-irradiated, there was a significant increase inStrigaattachments, highlighting the importance of the soil microbiome in disrupting parasite infection. In the presence of the soil microbiome, theStriga-susceptible sorghum plants performed similarly to threeStriga-resistant genotypes. This effect was lost when the soil microbiome was eliminated by gamma-irradiation. Subsequent analysis revealed thatStrigasubstantially affected the sorghum rhizosphere microbiome and that both the sorghum rhizosphere mycobiome and bacteriome composition significantly correlated withStrigaattachment. Interestingly, certain fungal species in the sorghum rhizosphere mycobiome were only detected whenStrigaseeds were present. Further investigation showed that these fungal taxa originated from theStrigaseeds and are known sorghum pathogens, suggesting a potential partnership betweenStrigaand fungal pathogens to invade their shared host. Overall, our study demonstrated that the soil microbiome influencesStrigainfection and sorghum performance in a genotype-dependent manner, and the microbiome ofStrigaseeds affects the composition of the sorghum rhizosphere microbiome.